Classification of isomeric C4H9O+ ions according the their unimolecular gas-phase decompositions

Isomeric C4H9O+(m/e 73) ions have been generated in the mass spectrometer from 12 different alcohols, ethers, acetals, and ketals. Using the criterion of competing metastable abundance ratios, these ions have been shown to decompose, with rate constants ca. 105 s–1, from one of five distinct structures or mixtures of structures. Extensive 2H-labelling has been used to investigate the structures of the decomposing ions, and the mechanisms of decomposition.